Re: Variable PTE_FILE_MAX_BITS

Pete Zaitcev (zaitcev@redhat.com)
Wed, 9 Apr 2003 02:19:38 -0400


> > would you be so kind to take this and forward to Linus?
> > I think this segment of the code is your brainchild.
>
> y'know, as I was writing that code I thought "no architecture could be dumb
> enough to make PTE_FILE_MAX_BITS variable".

Two different PTE formats.

> > + /* This needs to be evaluated at runtime on some platforms */
> > + if (PTE_FILE_MAX_BITS < BITS_PER_LONG)
> > + if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS))
> > + return err;
>
> The reason I didn't do this in the first place is that if PTE_FILE_MAX_BITS
> is 32 (as it is for ia32 PAE), the compiler generates a warning about the
> (1<<32). I guess it generates a bug, too.
>
> Ho hum. I shall make it "1ULL".

Wait, that would be a pessimization. Let me think about it.

I am thinking that perhaps I can arrange is so that the number
bits on different sparcs would end the same.

-- Pete
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